The source added that the young couple aren't unsure about their relationship—they just want to take the time to make their ceremony just right.

"We're told they feel they've made the commitment, and that's the most important thing," TMZ wrote.

As for critics who view their quick engagement as a sign of trouble ahead? "Justin's been in love with her for a long time, so this didn't just come from out of the blue," the source explained, adding that Baldwin and Bieber have been on-again, off-again for years.

While not much is known about the pair's upcoming nuptials, one thing is for certain: Baldwin's hoping Bieber will ditch the facial hair for his bridegroom look.